The present invention relates to a method of determining the thickness and/or the temperature of a metal strip having a strip width and cast by a casting device,                wherein the casting device has a die region into which is poured metal having a metal temperature that is greater than the solidus temperature of the metal,        wherein the casting device has a number of rotary elements delimiting the die region on one side in each case,        wherein each rotary element has surface elements which move cyclically along a respective rotation path at a respective rotational speed,        wherein                    the surface elements of the respective rotary element are immersed at a respective immersion point into the metal located in the die region,            during the further onward movement of the surface elements the metal solidifies on the immersed surface elements to form a respective strand shell,            the surface elements terminate contact with the respective strand shell at a draw-off point,            the metal strip is withdrawn from the die region at the draw-off point, and            the strand shells are constituent parts of the metal strip,                        wherein the surface elements of the respective rotary element                    require a respective cycle time for a complete revolution along the respective rotation path and            require a respective contact time for the onward movement from the respective immersion point to the respective draw-off point,                        wherein in addition to an enthalpy supply effected by the metal located in the die region the rotary elements exchange a respective enthalpy quantity with their environment per time unit.        
The present invention also relates to a computer program comprising machine code which can be processed directly by a computer and the processing of which by the computer causes the computer to perform a determination method of said type.
The present invention additionally relates to a computer programmed with a computer program of said type.
The present invention furthermore relates to a casting device for casting a metal strip having a strip width,                wherein the casting device has a die region into which is poured metal having a metal temperature that is greater than the solidus temperature of the metal,        wherein the casting device has a number of rotary elements delimiting the die region on one side in each case,        wherein each rotary element has surface elements which move cyclically along a respective rotation path at a respective rotational speed,        wherein the surface elements of the respective rotary element are immersed at a respective immersion point into the metal located in the die region and the metal strip is withdrawn from the die region at a draw-off point,        wherein the casting device is assigned a computer of said type.        
EP 0 736 350 B1 discloses a twin-roll casting device in which the profile of the cast strip is registered and a local heat flow coefficient is correctively adjusted in order to approximate the cast profile to a desired profile. A model is also used to determine the resulting curvature on the basis of the heat flow through the casting rolls. The heat flow through the roll is determined on the basis of the volume of coolant flowing through the roll and the temperature difference thereof.
WO 03/045 607 A2 discloses a twin-roll casting device in which a model-based calculation is carried out in order to adjust the structure and influence the profile of the metal strip.
With both approaches it is necessary to equip the casting device with an extensive system of sensors which is all the more susceptible to failure, the closer the sensors are arranged to the castable metal or to the cast strand that is still at casting temperature.
It is of course possible to arrange the sensors at a greater distance away. In this case, however, there is an increase in the dead time that elapses until the effect of a control intervention can be detected by the sensor system.